Something funky going on there Speed Demin. I canīt see it being an air leak if itīs running that rich and needed the lsn screwing in 3 turns. That would only make an air leak worse (leaner). If it was leaking air it would be machine gunning like crazy, not bogging down like that.
If you like, post the motor up to me fully assembled. I will strip it down bit by bit and check it out. I will get the Guru (Craig Underwood) to give it a pinch. Will put it back together and see if we can get it sorted. Hopefully you will then be able to get a few more months out of it. Got to keep mum happy eh